title: Food restriction differentially affects pituitary hormone mRNAs throughout the adult life span of male F344 rats.
abstract: Because neuroendocrine mechanisms may contribute to the antiaging effects of food restriction (FR), we measured the effect of FR on mRNAs encoding anterior pituitary (AP) tropic hormones. Slot blots or RNase protection assays were done on AP RNA from 3-, 6-, 12-, 18- and 24-mo-old male F344 rats consuming food ad libitum (AL) or food restricted (FR; to 60% of AL food intake) from 6 wk. Both AL and FR rats gained body weight during the study (P < 0.05), but FR rats weighed approximately 40% less (P < 0.0001). Messenger RNA levels were expressed in two ways, i.e., per total AP and per microgram total AP RNA. Proopiomelanocortin (POMC) mRNA/microg RNA was higher (P < 0.0005) in FR than in AL rats at all ages. Thyroid-stimulating hormone (TSH) beta mRNA declined with age (P < 0.05) in AL but not FR rats and was reduced by FR up to 12 mo (P < 0.01). Growth hormone (GH) mRNA/microg RNA declined with age (P < 0.05) in AL but not FR rats, and total GH mRNA in the AP was reduced by FR at early ages (P < 0.05). FR reduced prolactin (PRL) mRNA and its age-related increase (P < 0.0005). Levels of luteinizing hormone (LH) beta and follicle-stimulating hormone (FSH) beta mRNAs did not differ between AL and FR rats until 12 mo, but thereafter rose in FR (LH beta mRNA; P < 0.01, FSH beta mRNA; P < 0.05). Many of these changes in gene expression corroborate previously reported hormonal changes in FR rodents and mutant mice with extended life spans, and thus provide further support for the hypothesis that an altered hormonal milieu contributes to the antiaging effects of food restriction.
authors.affiliation: Department of Physiology, The University of Texas Health Science Center, San Antonio, TX 78229-3900, USA. Han@uthscsa.edu
authors.forename: E S
authors.initials: ES
authors.lastname: Han
authors.forename: T R
authors.initials: TR
authors.lastname: Evans
authors.forename: S
authors.initials: S
authors.lastname: Lee
authors.forename: J F
authors.initials: JF
authors.lastname: Nelson
mesh_terms: D000375:Aging; D000818:Animals; D001835:Body Weight; D005640:Follicle Stimulating Hormone / Q000235:genetics / Q000378:metabolism; D005502:Food; D005508:Food Deprivation; D013006:Growth Hormone / Q000235:genetics / Q000378:metabolism; D007986:Luteinizing Hormone / Q000235:genetics / Q000378:metabolism; D008297:Male; D023421:Models, Animal; D010903:Pituitary Gland, Anterior / Q000378:metabolism; D010907:Pituitary Hormones / Q000235:genetics / Q000378:metabolism*; D011333:Pro-Opiomelanocortin / Q000235:genetics / Q000378:metabolism; D011388:Prolactin / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011916:Rats, Inbred F344; D013972:Thyrotropin / Q000235:genetics / Q000378:metabolism
chemical_list: D010907:Pituitary Hormones; D012333:RNA, Messenger; D011333:Pro-Opiomelanocortin; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013972:Thyrotropin; D013006:Growth Hormone