Molecular identity, expression and functional analysis of interleukin-1alpha and its isoforms in rat testis.

Interleukin-1alpha (IL-1alpha) is a proinflammatory cytokine that has also been found to act as a paracrine mediator involved in the regulation of testicular functions. The present review provides an overview of the role of IL-1alpha in testicular physiology. Bioactive IL-1alpha isolated from adult rat testis was found to consist of three distinct immunoreactive protein species with apparent sizes of 45, 24 and 19 kDa. These isoforms showed bioactivity in a thymocyte proliferation and steroidogenesis assays with different biopotencies. The background of the molecular heterogeneity and processing, secretion and regulation of the isoforms of testicular IL-1alpha are discussed. All three isoforms have been found to be secreted into the testis tubular lumen and interstitial space. We have provided evidence that IL-1alpha is a paracrine factor that may be of importance in, e.g., the regulation of Leydig cell steroidogenesis. Pathophysiologically, testicular IL-1alpha may contribute to testicular relapse of acute lymphocytic leukemia in boys.

[Effect of genotype on hormonal function formation of Leydig cells during mouse postnatal development]. / Vliianie genotipa na formirovanie gormonal'noi funktsii kletok Leidiga v postnatal'nom razvitii myshei.

Changes in in vitro testosterone production by Leydig cells induced by chorionic gonadotropin, dibutyryl-cAMP, and pregnenolone have been studied during postnatal development of four inbred mouse strains BALB/c, PT, CBA/Lac, and A/He, with contrast hormonal activity of testes in sexually mature males. The interlinear differences significantly change with age of the males by all studied indices indicating genotype-dependent formation of hormonal activity of Leydig cells during postnatal development. Coordinated interlinear variability between all indices of Leydig cells reactivity has been established for each studied period of postnatal development. Hence, we have established coordinated interlinear genetic variability of hormonal function of Leydig cells, which was confirmed by considerable changes in it during postnatal development at puberty. Definitive genotypic differences in hormonal activity of Leydig cells appeared by late pubertal and early postpubertal development (day 60) and coincided with termination of morphological differentiation of Leydig cells and appearance of the differentiated cell population.

[The role of genotype in the formation of Leydig cell hormone function during postnatal ontogeny in diallele crosses of laboratory mice]. / Znachenie genotipa v stanovlenii gormonal'noi funktsii kletok Leidiga v postnatal'nom ontogeneze v diallel'nykh skreshchivaniiakh u laboratornykh myshei.

Production of testosterone by Leydig cells during the postnatal ontogeny in pubescence under in vitro stimulation by chorionic gonadotropin, dibutiryl-cAMP, and pregnenolon was studied in males of four inbred mouse lines (BALB/c, RT, CBA/Lac, and A/He) and their F1 reciprocal hybrids. Highly statistically significant association between the animal genotype and age was revealed for all parameters studied, which indicates the genotype-dependent formation of the Leydig cell hormone function during the postnatal ontogeny. The effect of genotype was characterized by two specific features. First, in each postnatal ontogeny stages examined correlative genetic variability in respect of the cAMP- and substrate-dependent indices of Leydig cell reactivity was observed. Second, during postnatal ontogeny coordinated genetic variability was subjected to substantial ontogenetic rearrangements. Definite pattern of genetic differences in the Leydig cell hormone activity was formed only at the late pubertal--early post- pubertal stage (60th day after birth). This process coincided with the completion of the Leydig cell morphological differentiation and the appearance of mature cells in the population. Thus, formation of the Leydig cell hormone activity during postnatal ontogeny is under coordinated genetic control, which is also subjected to substantial changes during pubertal differentiation.

Age-dependent stimulation of Leydig cell steroidogenesis by interleukin-1 isoforms.

Different isoforms of testicular interleukin-1 (IL-1) were analysed to determine whether there were differences in the ability to modulate rat Leydig cell steroidogenesis in vitro. Rat 17K IL-1alpha and IL-1beta, 32K IL-1alpha precursor (32proIL-1alpha) and a 24K splice variant (24proIL-1alpha) stimulated testosterone production by Leydig cells from 40- but not 80-day-old rats. The potency of the isoforms was IL-1alpha>IL-1beta>32proIL-1alpha>24proIL-1alpha, IL-1alpha being 50-fold more potent than IL-1beta. IL-1 receptor antagonist reversed the effects and IL-1 receptor type I mRNA was expressed by the responding Leydig cells, indicating a receptor mediated action. Inhibition of PKA and Ca(2+) channels abolished IL-1-induced steroidogenesis, while inhibition of PKC had no significant effect. Except for 24proIL-1alpha which was stimulatory, all IL-1 isoforms suppressed hCG-driven testosterone production. This inhibitory effect was abolished by androstendione, suggesting that P450c17 was suppressed by IL-1. Our results indicate that IL-1 plays a paracrine role in the regulation of Leydig cell steroidogenesis.

[Genetic control of the activity of microsomal enzymes of steroidogenesis in Leydig cells of inbred strains of mice]. / Geneticheskii kontrol' aktivnostei mikrosomal'nykh fermentov steroidogeneza v kletkakh Leidiga inbrednykh linii myshei.

Four activities of key microsomal steroidogenic enzymes (3 beta-hydroxysteroid dehydrogenase-isomerase, microsomal cytochrome P45017 beta, and 17-ketosteroid reductase) were compared in Leydig cells of six inbred strains of mice: A/He, CBA/Lac, C57BL/6J, DD, YT, and PT. The activities of the enzymes were found to vary considerably from one strain to another, depending on the genotype. Analysis of testosterone biosynthesis revealed a decreased activity of 17-ketosteroid reductase as compared to the activities of other microsomal steroidogenic enzymes. The metabolism of pregnenolone and progesterone demonstrated features dependent on the genotype and caused by genotypic differences in the activities of microsomal steroidogenic enzymes. These activities demonstrated a correlative interstrain variation indicative of their coordinated genetic control. The correlative variation may be related to a major gene effect on the activities of microsomal steroidogenic enzymes.

[Determination of metabolism of steroid hormones and activity of their synthetic enzymes in murine Leydig cells by high performance liquid chromatography]. / Opredelenie metabolizma steroidnykh gormonov i aktivnosti fermentov ikh sinteza v kletkakh Leidiga myshei metodom vysokoéffektivnoi zhidkostnoi khromatografii.

A very effective procedure was developed for separation of sex hormones of the delta 4 pathway using the microcolumn technique of high performance liquid chromatography (HPLC). A five-step gradient containing methanol, acetonitrile and water was used as a mobile phase, while Lychrosorb RP-18 with particles of 5 microns was used as a sorbent. Metabolism of steroid hormones and activity of 3 beta-steroid dehydrogenase, 17 alpha-hydroxylase, C17-20-lyase and 17-ketosteroid reductase were studied in Leydig cells of two mouse strains PT and A/He. The higher rate of steroid metabolism and of the enzymatic activity was detected in the mouse cells of PT strain as compared with those of A/He strain.

[Analysis of peripheral blood serotonin in domesticated silver foxes (Vulpes vulpes) as a major gene marker of domesticated behavior]. / Analiz serotonina perifericheskoi krovi serebristochernykh domestitsiruemykh lisits (Vulpes vulpes) kak maiorgennogo markera domestikatsionnogo povedeniia.

A segregation analysis of inheritance of the blood serotonin level in a domesticated silver fox population was performed (104 foxes from 4 pedigrees). The results of the analysis point to the effect of a major-gene in the control of this quantitative trait (dominance coefficient of lower level is 0.79), and suggest that breeding for domestic behavior is accompanied by selection against heterozygosity with respect to this major-gene. The lower blood serotonin level revealed in more domesticated foxes (p < 0.02) may be a consequence of this.