Serial maternal plasma concentrations of progesterone and estradiol during the morning, the afternoon and at night throughout normal pregnancy in the cynomolgus macaque.

Total progesterone (P4) and estradiol (E2) were determined in plasma from 10 pregnant cynomolgus macaques, Macaca fascicularis. A non-invasive blood collection technique utilizing a squeeze-cage and a catheter fixed momentarily in the brachial or saphenous vein allowed a 10-min serial blood sampling (SBS) for 3 h in the morning, the afternoon or at night at 30, 50, 70, 90, 110, 130, 150 and 165 days of pregnancy and on the day after delivery, without modifying gestation length or damaging fetal health. During an SBS session, extensive fluctuations of high P4 levels (greater than 10 ng/ml) were sometimes observed and infrequent pulses might occur, while E2 levels fluctuated only slightly but increased progressively. It is concluded that, even with the SBS method, individual differences in hormone patterns still occur throughout pregnancy. We suggest that a single daily P4 or E2 determination is not an accurate indicator of pregnancy normality.

Neuro-steroids: 3 beta-hydroxy-delta 5-derivatives in rat and monkey brain.

The rat brain accumulates pregnenolone (P) as the unconjugated steroid, the sulfate ester (S) and fatty acid esters (L). P + PS do not disappear from rat brain after combined adrenalectomy (adx) and castration (orx). PL does not serve a source of P after adx + orx. P is metabolized by several rat brain regions to progesterone and to PL. Brain microsomes contain the acyl-transferase which converts P to PL using endogenous substrates. Brain P and dehydroepiandrosterone (D) undergo a prominent circadian variation with their acrophases at the beginning of the dark span. The circadian variation of brain D persists after adx + orx. The monkey brain (Macaca fascicularis) also accumulates P and D. Adrenal suppression with dexamethasone for 4 days does not decrease the concentrations of brain P and 3rd ventricle CSFP and D. The concentrations of brain D are decreased to a much smaller extent than plasma D. D inhibits the aggressive behavior of castrated male mice exposed to lactating female intruders. This is not the case for DS or androst-5-ene-3 beta, 17 beta-diol. The D analog 3 beta-methyl-androst-5-en-17-one, which is not estrogenic and cannot be metabolized to testosterone or estradiol, is as active as D in inhibiting the aggressive behavior of castrated mice.

Plasma concentrations of testosterone, dihydrotestosterone, delta 4-androstenedione, dehydroepiandrosterone and oestradiol-17 beta in the crab-eating monkey (Macaca fascicularis) from birth to adulthood.

Plasma testosterone, 5 alpha-dihydrotestosterone (DHT), delta 4-androstenedione, dehydroepiandrosterone (DHA) and oestradiol-17 beta concentrations of crab-eating macaques after birth were analysed by RIA. The profiles of plasma testosterone and DHT exhibited four phases: (1) a neonatal phase (0 to 3-4 months of age) with considerable synthetic testicular activity; (2) a phase of 'infancy' (generally up to 29 months of age) during which the values of both androgens were low; (3) a prepubertal phase (generally up to 43 months of age) when circulating values oscillated with wider individual variations, and (4) a pubertal phase when the concentrations increased in parallel and concomittantly with the onset of meiosis and the establishment of spermatogenesis. The testosterone values continued to increase, reaching adult values at about 5-6 years of age, whereas DHT levels tended to stabilize from 4-5 years. Relatively high androstenedione values during the neonatal phase decreased progressively until puberty, then increased again slowly up to the adult stage when they plateaued at about neonatal levels. The DHA levels were high during the first months, decreased at about 1 year, remained stable during infancy and prepuberty and then declined again during puberty. At about 5 years, the values were 28% of those in neonates. There was no evidence of an adrenarche before the first signs of sexual maturity were observed. Oestradiol-17 beta concentrations were high at birth and until 3 months, then decreased and remained steady from 1 year of age until adulthood, except at the onset of puberty (27-30 months of age) when high values were again noted. Our results show that, during the neonatal period, the testis exhibited considerable secretory activity.

Relationships between Leydig cell morphometry and plasma testosterone during postnatal development of the monkey, Macaca fascicularis.

In neonates (0 to 3-4 months), the testis contained a mean number of 4.6 X 10(6) Leydig cells representing 4.2 % of its volume; Leydig cell cytoplasm contained 10.2 % of SER. In infants (up to 45 months), Leydig cells regressed but their number increased; their volume density did not change. Leydig cell cytoplasmic volume (454 microns3 ), which was about 2.5-fold less than in neonates (1 119 microns3 ) or adults (1 170 microns3 ), contained only 8.7% of SER. During meiosis stage (38-52 months). Leydig cell numbers and volume density did not vary but the cells reached a maximal size and an amount of SER comparable with that at birth was measured. When spermatogenesis was complete, the Leydig cells represented no more than 0.8% of testis volume, but their number and SER content were significantly increased. Except for a significant decrease when spermatogenesis was completed, Leydig cell lipid content did not change during development, and the volume density of mitochondria did not vary. The mean level of plasma testosterone was 2 ng/ml in neonates and 0.4 ng/ml in infants; it increased to 3 ng/ml during onset of meiosis and reached 10 ng/ml in adults. The profile of testosterone was positively and significantly correlated with the total volume and total number of Leydig cells (P less than 0.01 and P less than 0.02, respectively) and with changes in their cytoplasmic volume (P less than 0.001). Moreover, plasma testosterone levels were positively and significantly correlated with changes in Leydig cell SER content i.e. SER volume density and mean absolute volume per cell (P less than 0.001), total SER in the whole testis (P less than 0.01).

Quantitative study of testis histology and plasma androgens at onset of spermatogenesis in the prepuberal laboratory-born macaque (Macaca fascicularis).

Laboratory-born Macaca fascicularis underwent successive testicular biopsies and peripheral blood sampling during the peripuberal age. Testicular fragments were studied quantitatively on seminiferous cord or tubule histological cross sections. Plasma testosterone, androstenedione, and dihydrotestosterone were quantified by RIA. Enlargement of the diameter of seminiferous cords or tubules resulted from the increasing number of spermatocytes and the formation of the lumen. The number of Sertoli cells per cord or tubule cross section decreased abruptly at the onset of full spermatogenesis, and, as the tubules lengthened, the total number of these cells per testis remained constant. The number of A spermatogonia per cross section did not vary; consequently the total number per testis increased. The first spermatocytes appeared at 3-4 yr of age at a body weight of 3.24 +/- 0.15 kg, and full spermatogenesis was attained between 3 years, 8 months and 4 years, 4 months at a body weight of 3.5-3.8 kg. Plasma levels of androstenedione did not exhibit a clear pattern of variation, whereas plasma dihydrotestosterone and testosterone reached high levels with great fluctuations at the time full spermatogenesis was established. No relation between plasma testosterone level and the initiation of meiosis was observed.

Morphometry of fetal Leydig cells in the monkey (Macaca fascicularis), correlation with plasma testosterone.

The evolution of Leydig cells in Macaca fascicularis fetuses was followed throughout gestation (50-150 d) by morphometric procedures (volume densities of: cells, SER, mitochondria and lipid droplets). Testosterone from umbilical artery plasma was radioimmunoassayed starting on day 57. After predifferentiation and differentiation phases, Leydig cells entered the maturity phase (57-66 d), they occupied 19% of testicular volume, SER and lipid droplets represented 19% and 5% respectively of cytoplasmic volume. Then Leydig cells regressed dramatically (involution phase I: 66-83 d), their volume density decreased to 8%, that of SER to 12% whereas lipids doubled. Leydig cell volume density diminished to 5% during the second half of gestation (involution phase II), but their ultrastructure was not significantly altered. High plasma testosterone level (2.4 ng/ml) was observed during the maturity phase of Leydig cells, decline of testosterone occurred during involution phases I and II (1.13 and 0.58 ng/ml respectively). Its was shown that from day 57 to the end of fetal development the evolution of the plasma testosterone level correlated with the Leydig cell volume density and the SER volume density.

Annual plasma testosterone cycle and ejaculatory ability in the laboratory-housed crab-eating macaque (Macaca fascicularis).

Six fertile and healthy adult Macaca fascicularis males were studied. Radioimmunological assay of the plasma testosterone, sampled without anesthesia in the afternoon at the beginning of each month, showed an annual hormone cycle with a maximum (16.7 +/- 1.1 ng/ml) in the fall and a minimum (9.5 +/- 0.9 ng/ml) in the spring (fig. 1). Using the ratio: number of ejaculations/number of trials, the ejaculatory ability of these animals (fig. 2) was estimated for 10 min in the presence of females between days 12 and 15 of their menstrual cycle. This ability showed no cyclic variation during the year. Comparing the annual variation of testosterone levels in macaque males (Macaca mulatta, Macaca arctoides, Macaca nemestrina, Macaca fascicularis) and man, we found that, except for Macaca arctoides and Macaca nemestrina, the maximal simian levels always coincided with autumn and the minimal levels with spring in spite of the different rearing environments. (table 2). After studying ejaculatory ability and plasma testosterone level in the intact macaque throughout the year and comparing it to the results obtained by Resko and Phoenix (1972), Phoenix et al. (1973) and Michael and Wilson (1974, 1975) studying castrated males, we believe that above a minimal level, variation in the plasma testosterone level does not affect male sexual behavior, at least as far as ejaculatory ability is concerned. Moreover, during this study we noted that above a maximal plasma testosterone level, varying with the season, the ejaculation rate may be depressed (fig. 3).

An immunocytological study of the adult crab-eating macaque (Macaca fascicularis) pituitary and its cytological differentiation during fetal life.

The pituitaries of adult and fetal crab-eating macaques (Macaca fascicularis) have been studied by immunofluorescence using 15 antibodies against most of the known hormones in the adenohypophysis. The antibodies used were first checked on adult pituitaries for their cross-specificity with macaque pituitary hormones. We found five types of endocrine cells reacting positively, according to the biochemical relation of the molecules evidenced with one or more of the antibodies used. The sequential appearance of the various hormones in the cells of the anterior and intermediate lobes was then determined. The first hormones evidenced at day 45 of pregnancy were ACTH, beta-MSH, beta- and gamma-LPH and alpha- and beta-endorphins. alpha-MSH appeared at day 48 and STH at day 51. The glycoprotein hormones, LH, FSH and TSH, appeared at day 57 but the thyrotropes and gonadotropes did not attain their adult characteristics (staining intensity, morphology, density and distribution in the pituitary) until days 71 and 93, respectively. Prolactin was only found beginning at day 93 of pregnancy. The different specificity tests applied to the pituitary of the macaque, as well as to that of other vertebrates, show that the antibodies used have good specificity. A comparison of the dates at which the fetal pituitary gonadotropes appear in the macaque and the results of a developmental study of the external genital organs in that species indicated that the pituitary gonadotropic function is only established after somatic sex differentiation, which would thus probably occur independently.

A comparative study of the development of the fetal testis and ovary in the monkey (Macaca fascicularis).

The gonadal development of the Macaca fascicularis fetus was studied between 37 and 118 days on serial semi-thin and thin sections. The testis and the ovary began to differentiate at the same age (37 days); the definitive architecture of the testis was acquired at 43 days, while a cortex and a medulla did not form in the ovary until 55 to 60 days. In spite of the time-lag and the divergent development, the testis and the ovary evidenced three comparable stages; the main event of these stages was the centrifugal role of the mesonephros. The first stage (37-43 days) included the centrifugal and antero-posterior differentiation of the sex cord anlages from the mesonephric mesenchyme in contact with the proximal loops of the anterior tubules (for a detailed study see Dang and Fouquet, 1979). From 43 days (second stage), a remainder of the mesonephric mesenchymal blastema of the gonad supplied the rete system. The mesonephric tubules fused secondarily with that system which was connected to the sex cords. Whereas in the testis, the rete blastema did not play a direct role in organizing testicular structures, but only in forming excretory pathways, in the ovary, it invaded the medulla (whose initial sex cords degenerated) and penetrated to the ovigerous cords of the cortex. The rete ovarii blastema was probably the major source of periovocyte cells. The third stage included the differentiation of a steroidogenic interstitial tissue (from 50 days in the testis; at about 60 days in the ovary) and is further involution; these processes were similar in both sexes. Observation of the fine structure showed the development of the male and female gonocytes to be the same; the prespermatogonia and the oogonia could be characterized by the formation of nuclear vacuoles. The Sertoli cells and the periovogonial cells showed the same features.