Effects of Gender and Functional Overload on Plantaris Muscle Morphology in the Dwarf (HsdOla:dw-4) Lewis Rat

Document Type

Article

Publication Date

10-29-1999

Publication Source

Life Sciences

Abstract

To investigate relationships between pituitary function and gender on skeletal muscle growth and hypertrophy, fiber cross sectional area (CSA) and type were assessed in the plantaris muscle of normal and dwarf (Dw) male and female Lewis rats after 6 weeks of functional overload (FO). Serum growth hormone levels were 70–80% less in Dw rats of both genders and body mass was 62% greater in normal rats when compared to their Dw counterparts. Muscle weight was affected by gender, dwarfism, and FO as well as a significant gender∗Dw∗FO interaction. FO increased Type I, IIA, and IIX/B fiber CSA 120%, 102%, and 75%, respectively. Only type II fibers exhibited a reduction in CSA as a function of gender or dwarfism. Both type IIA and IIX/B fibers were affected by a significant gender∗Dw∗FO interaction. Our results suggest that the growth of type II fibers is sensitive to gender and pituitary function, while hypertrophy of type II muscle fibers is a function of the interaction between mechanical load, gender and pituitary function.

Inclusive pages

2489-2496

ISBN/ISSN

0024-3205

Comments

Permission documentation on file.

Publisher

Elsevier Inc.

Volume

65

Issue

23

Peer Reviewed

yes


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