EVIDENCE THAT THE OVARIES OF THE NEONATAL RAT SECRETE ACTIVE SUBSTANCES

Abstract

While physiological and biochemical data show that the testes of neonatal rats release androgenic substances capable of influencing morphogenesis and behavioural potentiality, equivocal evidence is available concerning the secretory capacity of the ovaries during this period. Presi, Jirásek, Horský & Henzl (1965) reported no detectable steroid-3β-ol dehydrogenase in interstitial cells around follicles in rats less than 8 days old. Using a bioassay method, Cierciorowska & Russfield (1968) found no reliable activity in ovarian extracts from rats younger than 13 days. Fluorometric analyses also failed to reveal significant amounts of oestrogen in ovaries from rats younger than 10 days (Presl, Hermann & Horský, 1969). Since Carmichael & Marshall's (1908) research, it is known that unilateral ovariectomy is followed by hypertrophy in the remaining ovary, presumably resulting from increased circulating gonadotrophin associated with decreased negative feedback by ovarian hormone. If the ovary of the neonatal rat does not secrete active hormones, then