Pregnancy promotes permanent body growth in wild-type and GH-deficient mice.

(A-C) Differences relative to baseline in body, lean, and fat mass in virgin WT (n = 15), primiparous wild-type (WT; n = 13), virgin Ghrhrlit/lit (n = 6), and primiparous Ghrhrlit/lit(n = 13). (D) Representative image showing differences in longitudinal growth between virgin and multiparous WT and Ghrhrlit/lit mice. (E-I) Body length, body weight, lean mass, fat mass, and liver mass in multiparous WT (n = 13) and Ghrhrlit/lit (n = 13) mice, relative to age-matched virgin WT (n = 15) and Ghrhrlit/lit(n = 12) mice. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. Statistical analysis was performed using two-way ANOVA and Holm-Sidak’s multiple comparisons test.

Growth is primarily induced during the first pregnancy.

(A-B) Changes in body weight and lean mass in wild-type (WT) virgins (n = 15), after the first pregnancy (n = 13), in virgins matched for age at the second pregnancy (n = 15), after the second pregnancy (n = 13), and after a late first pregnancy (n = 8). (C-D) Changes in body weight and lean mass in Ghrhrlit/lit virgins (n = 6), after the first pregnancy (n = 13), in virgins matched for age at the second pregnancy (n = 12), and after the second pregnancy (n = 13). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. Statistical analysis was performed using unpaired two-tailed Student’s t-test or one-way ANOVA and Newman-Keuls multiple comparisons test.

Evidence of post-pregnancy growth in women with isolated GH deficiency.

(A) In a cohort of women with isolated GH deficiency caused by a loss-of-function mutation in the GHRHR gene, nulliparous women (n = 8) were shorter than those with one or more pregnancies (n = 9). **, P = 0.009 (unpaired two-tailed Student’s t-test). (B) Comparison of foot size between two sisters with IGHD, one nulliparous and another primiparous. Image of the feet of two sisters with severe isolated GH deficiency caused by a homozygous loss-of-function mutation in the GHRHR gene. In addition to a larger shoe size, patient 2, who had a heterozygous son 9 years ago, is also taller than her nulliparous sister.

Increased GH secretion in pregnant WT mice but not in pregnant Ghrhrlit/lit mice.

(A-B) Representative examples of the pattern of GH secretion in two pregnant and virgin WT mice and in two pregnant and virgin Ghrhrlit/lit mice. (C-H). Total GH secretion, GH pulse frequency, pulsatile GH secretion, GH pulse amplitude, basal (non-pulsatile) GH secretion, and contribution of basal secretion to total GH secretion in virgin WT (n = 6), pregnant WT (n = 5), virgin Ghrhrlit/lit (n = 6), and pregnant Ghrhrlit/lit (n = 3) mice. The pregnant mice were at gestational ages 14-17 days. *, P < 0.05; **, P < 0.01; ****, P < 0.0001. Statistical analysis was performed using two-way ANOVA and Holm-Sidak’s multiple comparisons test.

Pregnancy differentially modulates hepatic GHR signaling in WT and Ghrhrlit/litmice.

(A-C) Western blot analysis to determine the hepatic expression of STAT5b and pSTAT5 proteins in virgin WT (n = 6), pregnant WT (n = 6), virgin Ghrhrlit/lit (n = 6), and pregnant Ghrhrlit/lit (n = 6) mice. (D-K) Serum IGF-1 levels and hepatic mRNA expression in virgin WT (n = 11), pregnant WT (n = 10), virgin Ghrhrlit/lit (n = 8), and pregnant Ghrhrlit/lit (n = 7) mice. The pregnant mice were at gestational ages 14-17 days. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. Statistical analysis was performed using two-way ANOVA and Holm-Sidak’s multiple comparisons test.

Pregnancy-induced body growth is preserved despite disruption of GH-, ghrelin-, and estrogen-related signaling pathways.

(A-C) The effects of first and second pregnancies on body weight, lean mass, and fat mass in control virgin (n = 10), control 1st pregnancy (n = 7), control second pregnancy (n = 5), AlbΔGHR virgin (n = 17), AlbΔGHR 1st pregnancy (n = 9), and AlbΔGHR second pregnancy (n = 6). (D-E) Body weight and lean mass in control virgin (n = 5), control 1st pregnancy (n = 14), GHSR KO virgin (n = 4), and GHSR KO 1st pregnancy (n = 13). (F-H) Body weight, lean mass, and fat mass in control virgin (n = 7), control 1st pregnancy (n = 4), AlbΔERα virgin (n = 7), and AlbΔERα 1st pregnancy (n = 4). (I-K) The effects of first and second pregnancies on body weight, lean mass, and fat mass in control virgin (n = 11), control 1st pregnancy (n = 11), control second pregnancy (n = 6), NestinΔGHR virgin (n = 6), NestinΔGHR 1st pregnancy (n = 6), and NestinΔGHR second pregnancy (n = 3). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. Statistical analysis was performed using two-way ANOVA and Holm-Sidak’s multiple comparisons test.