title: Involvement of activin and inhibin in the regulation of food and water intake in the rat.
abstract: The expression of activin and inhibin has been demonstrated in the hypothalamus, but their physiological roles in the brain remain to be elucidated. In the present study, involvement of activin and inhibin in the regulation of food and water intake was examined. Male rats were deprived of food or water for 12 and 60 hr, and mRNA levels of activin/inhibin alpha, betaA and betaB subunits in the hypothalamus were estimated by RT-PCR. Gene expression of alpha subunit transiently decreased at 12 hr of food deprivation, while it did not change during water deprivation. Food and water deprivation for 60 hr increased mRNA levels of betaA and betaB subunits, respectively. These results indicated that gene expression of each subunit was independently regulated. Injection of activin A (0.5 and 4.0 microg) into the third ventricle decreased food intake. Water intake was suppressed by 4.0 microg, but not 0.5 microg, of activin A. Intracerebroventricular injection of inhibin A (0.5 and 4.0 microg) decreased water intake in a dose dependent manner without affecting food intake, suggesting that inhibin could act independently of activin. Taken together, it is suggested that activin and inhibin take part in the central regulation of nutrient and fluid balance, though further study is needed to determine precise molecular species involved.
authors.affiliation: Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, Bunkyo-ku, Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Kubota
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Suzuki
authors.forename: Keitaro
authors.initials: K
authors.lastname: Yamanouchi
authors.forename: Michio
authors.initials: M
authors.lastname: Takahashi
authors.forename: Masugi
authors.initials: M
authors.lastname: Nishihara
mesh_terms: D028341:Activins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D004326:Drinking / Q000187:drug effects / Q000502:physiology*; D004435:Eating / Q000187:drug effects / Q000502:physiology*; D005508:Food Deprivation; D005786:Gene Expression Regulation; D007031:Hypothalamus / Q000378:metabolism; D007265:Inhibins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D013997:Time Factors; D014868:Water Deprivation
chemical_list: D012333:RNA, Messenger; D028341:Activins; D007265:Inhibins