Extragonadal effects of luteinizing hormone in mice.

LH is composed of isoforms which exhibit microheterogeneity. We recently demonstrated that a particular ovine or porcine LH preparation (G100-fr.3) stimulates kidney growth. This study was conducted to clarify the physiological role of this renotropic activity and other extragonadal effects of the ovine LH preparation in CD-1 mice. Hypophysectomy caused a significantly greater reduction in relative dry kidney weight (i.e. g/100 g body weight) when compared to adrenalectomy, castration, thyroidectomy, and castration plus thyroidectomy. Supplementation with G100-fr.3 in these animals partially restored not only kidney size but also DNA, RNA and protein content. Treatment with standard LH preparations (NIDDKoLH24 and G3-268DA), as well as PRL, GH, FSH and TSH, failed to reverse the renal atrophy induced by hypophysectomy and castration. Administration of testosterone to castrated hypophysectomized mice increased kidney weight and RNA content, but not renal DNA. The relative dry kidney weight increased significantly at the onset of puberty in intact male mice, but not in castrated males or intact female mice. In addition, human CG increased kidney size in hypophysectomized male mice, but not in castrated hypophysectomized animals. These findings indicate that LH isoforms may regulate kidney growth in the male mouse both directly as a renotropin stimulating hyperplasia and indirectly as a gonadotropin via testicular androgen, producing cellular hypertrophy. It was also noted that G100-fr.3 decreased hepatic weight, DNA, RNA and protein, but produced no significant change in the spleen, heart or adrenal glands in castrated-hypophysectomized mice. Such extragonadal effects of G100-fr.3 were also observed in intact female mice. These results suggest that certain LH isoforms may have extragonadal actions involving the kidney and liver.

Heterogeneity of sperm density profiles following 20-week therapy with high-dose LHRH analog plus testosterone.

Eight normal male volunteers received an LHRH analog, 100 to 500 micrograms daily, for 20 weeks. Testosterone enanthate, 100 mg, was given by injection every second week. Sperm density fell to 5.5 X 10(6)/ml and to 0 in two of the subjects receiving 100 micrograms, but was unchanged in the third. Three of the subjects who received 500 micrograms displayed azoospermia, whereas the other two showed no significant change in sperm density. The reasons for the heterogeneity are not clear. Only one of the three nonresponders had testosterone values that were higher than the other subjects. Gonadotropin levels were similar in responders and nonresponders. It is possible that the response to LHRH analog in man is determined by the extent of the reduction in LH bioactivity.

Partial purification and characterization of a renotropic fraction from ovine pituitaries.

It has been previously established that hypophysectomy leads to renal atrophy in rats and that a crude pituitary-derived fraction is effective in restoring kidney weight to the level expected for intact animals of the same body weight. This paper reports that considerable purification of the crude renotropic fraction from ovine pituitaries has been achieved and that the purified fraction is capable of restoring kidney weights of hypophysectomized castrated rats to normal values. For example, after five daily subcutaneous injections (135 micrograms/day) there were significant increases in dry kidney weight and total renal protein and DNA. The pituitary-derived fraction was devoid of somatotropin, contained only trace amounts of corticotropin, gamma-lipotropin, vasopressin, and prolactin, and had only low levels of thyrotropin and follitropin. Daily injections of prolactin, thyrotropin, and follitropin in doses of 20 micrograms each failed to stimulate renal growth in hypophysectomized rats. Thus, it seems highly unlikely that these factors are responsible for the observed renal hyperplasia after treatment with the pituitary fraction. The purified renotropic fraction had an isoelectric pH between 8 and 9. On polyacrylamide gel electrophoresis in the presence of detergent and a reducing agent, the renotropic fraction exhibited two major bands and one minor band with mobilities that corresponded to those of a standard lutropin preparation. The renotropic fraction exhibited considerable crossreactivity with an antiserum directed against the lutropin alpha subunit, suggesting the presence of the common glycoprotein hormone subunit. Moreover, the purified fraction stimulated steroid production by Leydig tumor cells in vitro. It is noteworthy, however, that standard ovine lutropin at 135 micrograms/day failed to exhibit renotropic activity in hypophysectomized castrated rats, although effects were noted at twice that dose. It appears that the renotropic activity represents a pituitary substance that can be separated from lutropin only with difficulty.

Surgical experience with hyperparathyroidism.

This is a retrospective analytic review of 208 patients with hyperparathyroidism studied and treated at Vanderbilt University Hospital from 1935 to 1980. Follow-up in these patients has been completed to date or to death in a great majority of patients. Results indicate the value of excision of isolated adenomas and of subtotal parathyroidectomy for primary and secondary hyperplasia.

Dopamine inhibits angiotensin-stimulated aldosterone biosynthesis in bovine adrenal cells.

The possibility that dopamine may play a role in the in vivo control of aldosterone production in man was suggested to us by reports from others; (a) that bromocriptine, a dopaminergic agonist, inhibits the aldosterone response to diuresis and to the infusion of angiotensin or ACTH; and (b) that metaclopramide, a dopamine blocking agent, causes elevations in plasma aldosterone levels. To determine whether such effects were direct or indirect, we examined the action of dopamine on aldosterone biosynthesis in isolated, bovine adrenal cells. Dopamine significantly inhibits the aldosterone response to angiotensin (P < 0.001), but does not influence basal aldosterone biosynthesis. It has previously been reported that angiotensin stimulates both the early and late phases of aldosterone biosynthesis. The present experiments demonstrated that the enhancing effect of angiotensin on the conversion of deoxycorticosterone to aldosterone (late phase of aldosterone biosynthesis) was almost completely inhibited by dopamine (P < 0.001). A significant inhibitory effect of dopamine (10 nM) was seen even when aldosterone biosynthesis was stimulated by a grossly supraphysiological concentration of angiotensin II (10 muM). However, these studies did not demonstrate any direct effect of dopamine on the early phase of aldosterone biosynthesis (cholesterol to pregnenolone) basally or when stimulated, or on the late phase of aldosterone biosynthesis under basal conditions. These in vitro studies suggest a direct inhibitory role for dopamine on the late phase of aldosterone biosynthesis, which may account for the in vivo inhibition of the aldosterone response to angiotensin in subjects treated with a dopaminergic agent.

Circulating levels of angiotensin I measured by radioimmunoassay in hypertensive subjects.

The development of a uniquely sensitive and specific antiserum to AI has led to the establishment of a radioimmunoassay capable of detecting 7.5 pg of AI per milliliter of plasma. Due to its sensitivity this assay permits the measurement of circulating levels of AI, obviating many of the controversial aspects of previously described AI assays which all required either an incubation step at 37 degrees C to allow renin to catalyze the formation of sufficient AI or an extraction procedure to concentrate sufficient peptide to make quantification feasible. Since the sensitivity of this assay also depends upon the availability of very pure trace, a method is described for preparing monoiodinated 125I-AI of specific activity greater than 1000 microCi/microgram. To demonstrate the versatility and sensitivity of this assay, changes in circulating AI levels in response to physiologic stimuli were measured. Blood samples were obtained from 88 subjects from the inferior vena cava below the renal veins in both the supine and upright positions. Values ranged from 12 to 1990 pg/ml of plasma. Eighty-five of the 88 displayed a rise in the AI level during an upright tilt, the mean for the group increasing from 220 to 385 pg/ml of plasma. Three subjects had samples drawn simultaneously from the inferior vena cava and a peripheral artery and/or vein. The amounts of AI in all three sampling locations were essentially the same. Seventeen patients with essential hypertension underwent an infusion of 1.5 L of normal saline, and circulating AI levels were determined before and 120 and 150 min after the start of the infusion. All 17 experienced suppression of their AI levels, the mean for the group at 0, 120 and 150 min being 177, 55, and 50 pg/ml of plasma, respectively. Circulating AI correlated well (r = 0.87009) with plasma renin activity in 226 samples from the renal veins and inferior vena cava from individuals with hypertension of various etiologies.

New mineralocorticoids: 5alpha-dihydroaldosterone and 5alpha-dihydro-11-deoxycorticosterone.

Mineralocorticoid activity of several delta4-3-ketosteroids and their 5alpha-dihydro analogs were evaluated by bioassay using urinary Na:K ratio of adrenalectomized rats as an index of mineralocorticoid activity. Among delta4-3-ketosteroids, aldosterone, 11-deoxycorticosterone, corticosterone, cortisol, 11-dehydrocorticosterone, and cortisone showed mineralcorticoid activity with aldosterone, the most potent of the series, showing virtually maximum activity at a dose of 0.25 microgram/rat. 5alpha-Dihydroaldosterone and 5alpha-dihydro-11-deoxycorticosterone possessed distinct mineralcorticoid activity, albeit less than aldosterone and 11-deoxycorticosterone. 5alpha-Dihydrocorticosterone, 5alpha-dihydrocortisol, 5alpha-dihydro-11-dehydrocorticosterone, and 5alpha-dihydrocortisone did not show mineralocorticoid activity in doses up to 100 microgram/rat. It is concluded that reduction of the 4.5 double bond diminishes mineralocorticoid activity of delta4-3-ketosteroids. Nevertheless, 5alpha-dihydroaldosterone has distinct mineralocorticoid activity with potency of 1.8% of that of aldosterone and approximately the same as that of 11-deoxycorticosterone.

Angiotensin stimulates cortisol biosynthesis in human adrenal cells in vitro.

Adrenal glands obtained from patients undergoing therapeutic adrenalectomy were used to study the effects of angiotensin on human adrenal steroidogenesis. It was observed that angiotensin stimulated cortisol biosynthesis. Although this has been demonstrated to occur in canine and bovine adrenals, angiotens in-induced cortisol biosynthesis has not been established in man. The possibility that angiotensin merely stimulated glomerulosa cells to secrete precursor steroids which accumulated in the medium and then diffused into fasciculata cells to provide substrate for cortisol biosynthesis was excluded by demonstrating that 3beta-hydroxy-5-pregnen-20-one (pregnenolone) and progesterone (the only pertinent precursors) did not accumulate in angiotensin-stimulated cell suspension. In addition, angiotensin stimulated cortisol biosynthesis in a fasciculata cell suspension in which angiotensin did not stimulate aldosterone production. Therefore, in human adrenal cell suspensions angiotensin appeared to act directly to stimulate cortisol synthesis by fasciculata cells. In normal subjects pre-treated with dexamethasone, angiotensin infusions failed to stimulate an increase in plasma cortisol. The physiological importance of angiotensin as a regulator of cortisol secretion remains, therefore, to be established.

Results of treating childhood Cushing's disease with pituitary irradiation.

To determine the usefulness of conventional pituitary irradiation in childhood Cushing's disease, we reviewed the results of this treatment in 15 patients. Twelve were cured (mean plasma cortisol of less than 10 microgram per deciliter and 24-hour urinary 17-hydroxycorticosteroid excretion of less than 7 mg per gram of creatinine) within 18 months, and 10 of the 15 were cured within nine months. Three failures required bilateral adrenalectomy. Growth resumed in 12, with adult heights of 156 to 166 cm. Sexual development proceeded normally in all 15, with normal secondary sexual characteristics and sexual function, and demonstrated fertility in four married adults. Intellectual function appeared normal. Basal and stimulated hormone levels were normal, except for subnormal (5 ng per milliliter or less) growth hormone levels after hypoglycemia in one of 12 patients. There were no complications of therapy and no progressive pituitary enlargement or hyperpigmentation. Pituitary irradiation is safe and effective therapy for childhood Cushing's disease.