Dissociation of Luteinizing Hormone and Follicle-Stimulating Hormone Control Mechanisms in Male and Female Rats by Neonatal Administration of Estradiol Benzoate or Testosterone Propionate

Abstract

Testicular atrophy (TA) and decreased plasma luteinizing hormone (LH) levels were observed in the adult male rat after treatment with 500 µg of estradiol benzoate (EB) on the first day of life, while administration of 1 mg of testosterone propionate (TP) on the same day was also associated with TA but increased LH levels. TA and no changes in plasma LH levels were seen when the treatment was performed with similar doses of both steroids on day 5 of life. In no case were plasma follicle-stimulating hormone (FSH) levels altered by these treatments. No differences in basal LH and FSH levels were found in adult females after treatment with 100 µg of EB or 1 mg of TP on day 5. LH response to castration was lower in neonatally androgenized and estrogenized adult male and female rats than in their respective controls, while FSH response was scarcely modified. In conclusion, neonatal treatment with EB or TP in both sexes induced alterations in LH control mechanisms without changing those of FSH.

Neonatal exposure to estrogen differentially alters estrogen receptor alpha and beta mRNA expression in rat testis during postnatal development

“…To this end, 1-day-old male rats were injected s.c. with a single dose of EB (500 µg/rat); this protocol was selected on the basis of our previous studies as it was found to be the most effective in inducing complete estrogenization in the male rat (Aguilar et al 1984, Bellido et al 1985, 1990, Pinilla et al 1992. Vehicle (oil)-injected rats served as controls.…”

“…In male rodents, it is well established that exposure to supra-physiological doses of estrogens during the critical period of neonatal differentiation results in an array of permanent reproductive defects, which include atrophy of testes and sexual accessory glands (Kincl et al 1965, Brown-Grant et al 1975, Aguilar et al 1984, Newbold & McLachlan 1985, Naslund & Coffey 1986, impaired maturation of germ, Sertoli and Leydig cells (Gaytán & Aguilar 1986, Pinilla et al 1992, altered luteinizing hormone (LH) secretion (Aguilar et al 1984, Pinilla et al 1995, and inappropriate puberty onset (Brown-Grant et al 1975, Bellido et al 1985. Disruption of reproductive function by neonatal estrogenization is probably a multifaceted phenomenon, and complete elucidation of the mechanism(s) involved is still pending.…”

Quantitative analysis of Sertoli cells in neonatally oestrogen-treated rats

“…In the adult rat, androgens seem to be the most important hormones for testicular function (Bressler, 1976). Neonatally oestrogenized rats have an altered hormonal pattern during prepubertal development (Aguilar et al, 1984;Bellido et al, 1985), and Leydig cells are not differentiated at 45 days of age in these animals (Gaytan et al, 1986). Steroid hormones alter the nuclear structure in many organs, such as the central nervous system (Cohen et al, 1984) and the male sex accessory glands (Arnold et al, 1983), and a possible direct effect of oestrogens cannot be excluded from the present results.…”

“…Neonatally oestrogen-treated rats present several hormonal alterations during prepubertal development (Aguilar et al, 1984;Bellido et al, 1985), as well as an impaired maturation of various testicular cell types (Ohta & Takasugi, 1974;Gaytan et al, 1986). The (Elias & Hyde, 1980) corresponded to the nuclear diameter parallel to the basement membrane and was 4-86 ± OTOpm and 6-98 ± 016 pm for control rats at 22 and 45 days of age respectively, and 3-54 ± 0-17 pm and 5-42 ± 0-20 pm for oestrogen-treated rats at the same ages (mean ± s.e.m.…”

Effects of the Intraventricular Administration of 5,7-Dihydroxytryptamine on FSH, LH and Prolactin Secretion in Neonatally Estrogenized Male Rats

“…Some data suggest that 5-HT stimu lates LH secretion [Wuttke et al, 1977;Van de Kar et al, 1980;Chen et al, 1981;Ruzsas et al, 1982] whereas others show the oppo site [Kamberi et al, 1970;Ladosky and Noronha, 1974;Pilotte and Porter, 1979], From the few available data regarding the effects of serotonin on FSH secretion, both an inhibi tory action and no effect have been described [Kamberi et al, 1971;Wuttke et al, 1977;Ruzsas et al, 1982], It has been generally agreed that rats neonatally injected with sex steroids show changes in gonadotropins and prolactin se cretion in adulthood [Mallampatli andJonson, 1973a, b, 1974;Mogiulevski et al, 1978;Aguilar et al, 1984] together with modifica tions in their aminergic systems [Vaccari. 1980;Demurest et al, 1981;Lookingland et al, 1982],…”