title: Body growth and plasma concentrations of metabolites and metabolic hormones during the pubertal period in female Shiba goats.
abstract: It has been shown in various species that the onset of puberty is closely associated with body growth and nutritional state rather than age. The present study was conducted to determine the timing of puberty and to clarify body growth and metabolic changes around the pubertal period in female Shiba goats. Blood samples were collected between 10 to 38 weeks of age from 12 female goats, and plasma concentrations of progesterone, metabolites (glucose, nonesterified fatty acid, ketone body and acetic acid) and metabolic hormones (insulin and insulin-like growth factor-I (IGF-I)) were analyzed. Physical parameters (body weight, withers height and body length) were also measured at the blood sampling. The week when plasma progesterone concentrations first exceeded 1.0 ng/ml was designated as the onset of puberty. The results showed that the average age of the onset of puberty was 27.0 +/- 0.9 (mean +/- SEM) weeks in female Shiba goats. When the goats reached puberty, the average values of body weight and goat body mass index ((body weight (kg)/withers height (cm)/body length (cm)) x 10(3)) were 12.2 +/- 0.5 kg and 5.7 +/- 0.2, respectively. No particular change associated with puberty was apparent for plasma concentrations of the metabolites examined. Plasma insulin concentrations were maintained at lower levels until the onset of puberty, and then they began to gradually increase. Plasma IGF-I concentrations began to gradually increase 1 to 4 weeks before the onset of puberty and this increase continued throughout the peripubertal period. These results imply that IGF-I acts as a peripheral nutritional signal to trigger the onset of puberty in Shiba goats.
authors.affiliation: Laboratory of Neuroendocrinology, National Institute of Agrobiological Sciences, Tsukuba, Japan.
authors.forename: Katsuyasu
authors.initials: K
authors.lastname: Sakurai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ohkura
authors.forename: Shuichi
authors.initials: S
authors.lastname: Matsuyama
authors.forename: Kazuo
authors.initials: K
authors.lastname: Katoh
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Obara
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okamura
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000367:Age Factors; D000818:Animals; D001699:Biometry; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D005947:Glucose / Q000378:metabolism; D006041:Goats; D006728:Hormones / Q000097:blood* / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis*; D007659:Ketones; D010949:Plasma / Q000378:metabolism; D011374:Progesterone / Q000097:blood; D013997:Time Factors
chemical_list: D006728:Hormones; D007328:Insulin; D007659:Ketones; D011374:Progesterone; D007334:Insulin-Like Growth Factor I; D005947:Glucose; D019342:Acetic Acid