Effect of Underfeeding, Hemigonadectomy, Sex and Cyproterone Acetate on Serum FSH Levels in Immature Rats

Stewart, Sheila F.; Kopia, Susan; Gawlak, Daniel

doi:10.1530/jrf.0.0450173

Cited by 11 publications

(1 citation statement)

References 14 publications

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“…Hemiorchidectomy has been reported to raise the concentration of FSH in immature male rats (Ojeda «fe Ramirez, 1972;Ramirez «fe Sawyer, 1974;Stewart, Kopia & Gawlak, 1975;Moger, 1977a;Cunningham, Tindall, Huckins «fe Means, 1978). However, Moger (1977a) found that a 40% increase of endogenous FSH in rats hemiorchidectomized at 25 days of age did not alter responsiveness of the testis to exogenous LH between 30 and 39 days of age.…”

Section: Introductionmentioning

confidence: 99%

Effect of Prepubertal Hemiorchidectomy on the Response of the Testis to Luteinizing Hormone

Selin¹,

Moger²

1979

Journal of Endocrinology

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Administration of FSH to hypophysectomized male rats has been shown to increase the capacity of the testes to secrete testosterone in response to LH. Studies were done to assess the effect of increased endogenous FSH on the response of the testis to LH. At 17 and 24 days of age, animals hemiorchidectomized at 10 days of age had significantly higher serum FSH levels and testicular weights than sham-operated rats. To study the testicular response to LH in vivo, hemiorchidectomized animals were sham-operated and the sham-operated animals were hemiorchidectomized at 17 or 24 days of age. Luteinizing hormone (30 \g=m\g/100g body wt) or saline was administered immediately after the operation and the animals were autopsied 90 min later. Chronic hemiorchidectomy significantly increased the serum testosterone response to LH at 17 but not at 24 days of age. The testicular response to LH in vitro was also investigated. Testes from rats hemiorchidectomized or sham-operated at 10 days of age and killed at 17 and 24 days of age were incubated for 3 h in the presence or absence of 100 ng LH/ml incubation medium. Significantly more 5\g=a\-androstane-3\g=a\,17\g=b\-diol and androsterone were produced by the testes from hemiorchidectomized than from sham\x=req-\ operated animals at 17 days of age but not at 24 days of age. The production of testosterone in vitro was not influenced by hemiorchidectomy at either age. These results suggest that serum FSH concentration is the factor limiting LH responsiveness before but not after the prepubertal increase in FSH levels. However, treatment of intact rats from 10 to 16 days of age with 20 \g=m\g rat FSH/day did not increase the serum testosterone response to LH.

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Section: Introductionmentioning

confidence: 99%

Effect of Prepubertal Hemiorchidectomy on the Response of the Testis to Luteinizing Hormone

Selin¹,

Moger²

1979

Journal of Endocrinology

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Growth patterns and hormonal profile of male rats with protein‐calorie malnutrition

Herbert

1980

Anat. Rec.

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A condition of protein-calorie malnutrition was precipitated in young Sprague-Dawley male rats at 20 days of age using an 8% low protein diet (LPD). At five-day intervals for up to 50 days of age, the rats were studied to determine the effect of an LPD on the reproductive axis of the endocrine system. Daily monitoring of the body weight, as well as the consumption of food, kilocalories, and protein was conducted. The same parameters were followed over the identical time period in a group of animals desigated as controls which were fed a standard laboratory diet (SLD) containing 27% protein. The controls showed a linear growth rate over the 30-day experimental period. In comparison, the malnourished rats grew more slowly so that by 50 days of age, their mean body weight was 68.9 +/- 3.1 g as compared to 248.1 +/- 6.1 g for the controls. The daily food, kilocalorie, and protein intake by the experimental animals were also appreciably less. The pituitary gland, ventral prostate gland, testes and liver were smaller in the animals fed the LPD. This was observed as early as five days after initiating the dietary regimes and remained a consistent observation until the end of the experiment. In general, the absolute weights of these organs in the 50 day-old malnourished rats were similar to those found in 25 to 26-day-old animals fed the SLD. The relative weights of the pituitary gland and liver remained similar between the two animal groups. The testes and ventral prostate gland, however, were relatively smaller in the malnourished animals at nearly every time interval studied. On light microscopic examination of the testes, it was found that normal maturation of the germ cells failed to occur in all but one of the experimental animals, whereas maturation proceeded normally in the rats fed the SLD. Serum luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL), and testosterone were lower in the malnourished animals at all ages studied. These hormones not exhibit the fluctuations that were seen in the controls and are typical in rats that are becoming sexually mature. The effect of protein deficiency on the concentration of the pituitary gonadotrophins was more varied. FSH concentrations were consistently lower, PRL was moderately affected, and LH remained essentially unchanged. Hypothalamic LH-releasing hormone was measured and found to be significantly less in the rats fed the LPD at most of the time intervals examined. These results indicate that the hypothalamo-hypophyseal-gonadal axis is impaired when the consumption of proteins and calorie is decreased. The possible involvement of extrahypothlamic centers in the control of hormone secretion in the protein-deficient rat is discussed.

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Altered Testosterone Feedback in Pubertal Male Rats Raised on Reduced Caloric Intake

Piacsek

Bonifer

Tan

1986

Journal of Andrology

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A study was conducted to explore the hypothesis that reduced caloric intake increases the negative feedback efficacy of testosterone on gonadotropin secretion. Daily subcutaneous injections of testosterone propionate in oil were administered to either age-matched (37-day-old) or weight-matched (mean = 178 g) ad libitum-fed (control) or underfed rats that received 60% of normal daily food intake from the age of 20 days. Daily doses of testosterone propionate ranged from 25 to 400 micrograms/100 g body weight. Results indicate that reduced caloric intake increases the suppression of serum LH by testosterone propionate in both age-matched and weight-matched underfed rats. On the other hand, the response of serum FSH concentrations to testosterone propionate was affected by reduced diet only in the weight-matched animals. Results suggest that the increased negative feedback of testosterone on LH secretion is a specific diet-induced effect and not merely the result of reduced growth. The altered response in FSH secretion, however, may represent age-associated changes in sensitivity to testosterone rather than diet-induced effects.

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Effect of Underfeeding, Hemigonadectomy, Sex and Cyproterone Acetate on Serum FSH Levels in Immature Rats

Cited by 11 publications

References 14 publications

Effect of Prepubertal Hemiorchidectomy on the Response of the Testis to Luteinizing Hormone

Effect of Prepubertal Hemiorchidectomy on the Response of the Testis to Luteinizing Hormone

Growth patterns and hormonal profile of male rats with protein‐calorie malnutrition

Altered Testosterone Feedback in Pubertal Male Rats Raised on Reduced Caloric Intake

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